The present invention concerns a flexible circuit board connecting structure which is used to connect a flexible circuit board (such as a flexible printed circuit, FPC) that has a ground surface with another circuit board.
An example of a conventional technique of this type is disclosed in Japanese Patent Application Kokai No. 10-284201. That patent application discloses a board-mounted connector mounted on a circuit board, and a relay connector which terminates a flexible circuit board that has a ground surface, and which can be engaged with the board-mounted connector. The relay connector has a plurality of signal contacts which are used to make connections with the signal circuit traces of the flexible circuit board, an insulating housing which accommodates these signal contacts, and a shielding assembly which is disposed so that it surrounds the insulating housing. In other words, in the relay connector, the signal circuit of the flexible circuit board is connected to the signal contacts, and the ground surface is connected and electrically grounded to the shielding assembly disposed on the outer circumference.
The board-mounted connector disclosed by Japanese Patent Application Kokai No. 10-284201 has a plurality of signal contacts, a housing which accommodates these signal contacts, and a shielding member which is disposed around the outer circumference of the connector. When the relay connector is engaged with the board-mounted connector, the contacts are electrically connected to each other, and the shielding assembly and shielding member are both connected. In this way, mutual signal and ground connections are realized between the flexible circuit board and the other circuit board.
In the technique disclosed in the abovementioned patent application, manufacture and assembly are difficult, so that the cost of the device is increased. Furthermore, in cases where a large external force is applied to the flexible circuit board, there is a danger that the mutual engagement of the contacts will be released. This is disadvantageous for special applications. Accordingly, the first object of the present invention is to realize a highly reliable and comparatively simple construction for making connections between a flexible circuit board with a ground surface and another circuit board. A second object of the present invention is to provide a flexible circuit board connecting structure which makes it possible to maintain highly reliable signal and ground connections even in cases where a large external force is applied to the flexible circuit board.
The present invention provides a flexible circuit board connecting structure in which a flexible circuit board that has a ground surface and a second circuit board are connected via a board-mounted connector which is mounted on the second circuit board. A metal conductive supporting plate is connected to the ground surface and supports an engaging end portion of the flexible circuit board accommodated in the board-mounted connector. The metal conductive supporting plate is crimped on the flexible circuit board, and is connected to a grounding means installed in the board-mounted connector. The conductive supporting plate may be mechanically engaged with the grounding means.
The present invention also provides a flexible circuit board connecting structure in which a flexible circuit board that has a ground surface and a second circuit board are connected via a board-mounted connector which is mounted on the second circuit board, and the flexible circuit board is fastened in the connected position with the board-mounted connector by screw means. The grounding connection between the flexible circuit board and the board-mounted connector is realized by means of a driving force directed toward the second circuit board by the screw means. The board-mounted connector may be equipped with a temporary holding means that temporarily fastens the flexible circuit board prior to the fastening effected by the screw means.
Additionally, the board-mounted connector is equipped with conductive members that are connected to the second circuit board, and the ground surface of the flexible circuit board forms a ground path that extends to the second circuit board via the conductive members. The board-mounted connector also has a grounding shell which is installed so that this grounding shell surrounds the outer surface of the board-mounted connector, and the grounding shell is constructed so that it makes electrical contact with the members.